


Instinct

by The_Winter_Writer



Category: Marvel Cinematic Universe, The Avengers (Marvel) - All Media Types
Genre: Alpha Bucky Barnes, Alpha/Beta/Omega Dynamics, Alternate Universe - Canon Divergence, Bonding, Bottom Tony Stark, Knotting, M/M, Mates, Mating Cycles/In Heat, Omega Tony Stark, Possessive Bucky Barnes, Pre-Iron Man 1, Protective Bucky Barnes, Top Bucky Barnes, True Mates, Winter Soldier Bucky Barnes, hinted assassination, smut and a hint of plot
Language: English
Status: Completed
Published: 2017-10-13
Updated: 2017-10-13
Packaged: 2019-01-16 18:31:29
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,474
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12348249
Author URL: https://archiveofourown.org/users/The_Winter_Writer/pseuds/The_Winter_Writer
Summary: Of course Tony would run into his true mate after the Alpha had assassinated another guest at the same gala he was trying to escape from without incident. Who wanted a fairy tale meeting anyway? Those kinds of meetings were not meant for billionaire Omegas.





	Instinct

**Author's Note:**

> This is my first attempt at WinterIron because I found these two impossible to resist and I wanted to play around in the ABO world.

It certainly wasn’t some kind of fairy tale meeting. It wasn’t anything typical or normal. Nothing like anything he’d heard over the years and certainly nothing he’d personally imagined. Honestly Tony had never expected to meet the one Alpha, his Alpha, at any point in his life. He had, in fact, been doing his best to avoid anyone actually realizing he wasn’t a Beta but it looked like that was going to be thrown out the window in a very spectacular fashion.

_Fuck. Barely made it to twenty-four._

Tony shifted, eyes darting to the left and right, as the tell-tale tightening in his gut reaffirmed exactly what this was. His body knew exactly what the Alpha dressed like he’d stepped out of a bondage fantasy was to him. Nothing would have completely destroyed his hard earned control or the suppressants helping to mask the Omega in his scent. Part of him was relieved. He wouldn’t have to hide anymore. There wouldn’t be a reason for it. No excuse. Another part was terrified at the implications that would follow the reveal of what he truly was: an Omega.

 _Howard_ _must be rolling over in his fucking grave._

Every single movement drew the attention of the Alpha stalking towards him. Each step his Alpha took was purposeful and predatory. Tony swallowed roughly and shifted on his feet. It shouldn’t be that fucking hot but there was something about the air of danger, violence and strength that was very unexpectedly doing something for him. He’d gone out of his way to avoid Alphas but right now Tony was wondering why. A mask obscured the lower half of the Alpha’s face, dark hair hung loose and powerful shoulders remained squared. The pose reminded him of a soldier. It reminded him of a warrior.

Confident.

Deadly.

Purposeful.

Focused.

All of that was locked onto him with a single-minded kind of intensity that had him breathless in anticipation.

Tony didn’t move. A deep longing inside of him called out, his scent changing with the release of soft Omega pheromones to tempt a mate –his mate– into claiming him, even as a low burning need continued to twist in his gut. The Alpha’s eyes were piercing, an almost steel blue-grey, and Tony knew his were an Omega gold. Fuck fuck fuck.

He was wearing one of his best suits, there was a gala going on he’d been trying to escape and the Alpha in front of him was armed to the teeth. Tony was almost positive the sound he’d heard shortly before he’d caught sight of the Alpha had been a muffled gunshot.

This had all the makings of a bad porno or maybe a really, really good one because now the Alpha was pressing up against him, a warm line of solid muscle that had him pinned against a cool wall. Tony sucked in a surprised breath and took in the scent of leather, gun oil and something that immediately made him think of the crisp and sharp refreshing air of winter. It made him want to bear his neck and whine in a completely unexpected way. He wanted to snarl at his lack of control but in this moment he wasn’t supposed to care about control.

This meeting was supposed to be about a complete lack of control. Two pieces finally meeting and connecting on a level that no one could truly explain.

“Mine.” It was the first thing the Alpha had said in English. What Tony had caught, on his way out of the building, had been a low and threatening Russian that had caused him to pause in his escape and a muffled kind of sound he’d told himself wasn’t a silencer.

It had been a pause that was long enough that the Alpha had stumbled across him and Tony had caught a whiff of his scent. That had been all it had taken. Something had snapped right into place and everything seemed to tilt on its axis in a completely unnecessary cliché moment he would deny to his dying day.

The hand that rested against his neck, fingers lightly grazing his jaw, was cool and metal. Tony’s mind roiled at the knowledge even as a low sound slipped from his lips and he tilted his head, offering his neck to the Alpha. Fingers stroked his skin and Tony could practically feel the satisfaction rolling off the dangerous Alpha in waves. There was a low kind of whir from the mechanics in the arm, a whole metal arm, and that had the engineer in him practically purring. It made the Alpha that much more appealing. An impossible combination that hit so many right notes that Tony was surprised how right the Alpha before him felt instinctively.

Tony almost started when the right hand, the flesh hand, curled possessively at his hip and the strength was even more evident. Then it became even more evident when he found himself hauled away from the wall, from the room the Alpha had come from and away from the gala in an effortless kind of way that shouldn’t have been possible even with an Alpha’s strength. The sound of voices and music faded until he found himself in an empty room, the door locked behind them and he was still alone with the Alpha.

The heat that had been steadily building and building inside of him, coiling in his gut and at the base of his very spine, seemed to practically explode into an impossible to ignore inferno. “If you don’t get your hands on me in the next few minutes I think I’m going to go insane.” Because he was slowly starting to go out of his mind. It was almost as though the Alpha had been waiting for that because Tony found his clothing being removed in record time, tossed to the side in a discarded heap, until he was completely naked and the Alpha was still covered near head to toe in leather. “How—?” he was cut off when strong hands gripped him and Tony found himself being carried over to a couch he was very sure wasn’t meant for fucking.

Or maybe it was?

The Alpha bent him over the edge so his ass was offered up and Tony whined at the denial of getting to actually see his Alpha naked. Fingers ghosted over his warm skin sending shivers and spikes of pleasure pulsing through him. Tony was slick and loose and aching. His suppressants had failed in the face of his true Alpha and Tony was drowning in sensation. Metal fingers rubbed against his hole and two of them sunk in, eased by his arousal and the brief mating heat his Alpha’s pheromones had triggered, causing a low, desperate keen to escape.

Fuck.

Fuck fuck fuck _fuck_

Tony’s mouth fell open as his cheeks flushed with arousal and he braced his hands on the couch trying to shove himself back, trying to take those metal fingers deeper, before a hand braced on his back and the Alpha kept him pinned in place. Metal fingers fucked in and out of him, scissoring and rubbing, while Tony lost his mind. It felt so fucking good, so fucking amazing, to be full and pressed in place by the one Alpha that was meant for him.

His mind was slowly but surely drifting on the sensation of pleasure and Alpha and full as two fingers became three. They pumped through his slick hole, spreading him wide and making him loose, while he whined, whimpered and started to beg. If he was in his right mind his cheeks would probably be flushed in embarrassment but in the face of this Alpha it was impossible not to want to submit.

It was impossible not to give in and be taken care of in a way that he had never let himself indulge in before. It felt so good to be the complete focus of someone like this, someone who wanted him because they truly fit together, instead of going after him for the purpose of his money or weapons. He could tell by the forming bond, already starting to connect them even before his bonding gland was broken, the truth of it. This wasn’t fake, it wasn’t someone wishing to tie themselves to Tony Stark and he just wanted to give in.

So he did.

The fingers slipped free and Tony released a sound of protest, clenching down at the disappointing feeling of empty, until he heard the sound of clothing shifting. He turned to look and caught the sight of his Alpha freeing himself, hard and impossibly big, before the Alpha was stepping up and the blunt, thick head of the Alpha’s cock pushed against him. It pushed in, spreading him wide, before it started to sink in.

Tony’s mouth fell open and his breathing started to come in quick, harsh pulls as inch by inch the Alpha buried himself inside. It ached, burned and felt so fucking right all at once that Tony’s mind was starting to fuzz over at the overload of sensation. The fire in his veins was blazing and warm as his mating heat set in completely. It was only a brief heat triggered by meeting a true mate but it felt like it could last days and he’d welcome every second.

Fingers curled at his hips, gripping tight and holding him in place, while the Alpha kept thrusting in. Tony panted, fingers dug into the couch, as his ass stretched wide. Finally heavy balls pressed up against his ass and every single inch of his Alpha was buried inside him.

He’d never felt so full in his life.

“Fuck.” Tony shifted as warm hands gripped his hips firmly and the Alpha rolled his hips back, the tip of his cock just staying inside of Tony, before slamming back in with a force that rocked Tony forward. He couldn’t keep his hands braced from the strength of the thrust and instead found himself gripping the cushion as his Alpha started to fuck into him. The sweet, slowness of being fingered open and fucked full of a cock for the first time was lost to a wild kind of fucking that was sending delicious jolts of pleasure racing through him.

It was a pace he couldn’t have hoped to match even in a different position.

The slap of skin on skin filled the room along with the wet slide of a thick cock through a slick filled hole but it was nothing on the sounds his Alpha was practically ripping from him. Tony was lost to moans and loud whines as thrust after thrust nailed his prostate causing his breathing to quicken. The tightness in his gut only coiled more and more, the building of his orgasm sending even more heat twisting inside of him, as each thrust dragged him closer and closer to release.

He was going to come untouched.

“Alpha. Fuck. Alpha please Alpha Alpha Alpha.” Dignity and control had been thrown out of the window. He didn’t fucking care about either of them. If there was one situation it shouldn’t matter it was this one. “So close. Please please please.”

The catch of a growing knot on his rim had Tony seeing white and his ability to form words seemed to disappear. He needed a knot. He needed his Alpha’s teeth in the back of his neck and their bond sealed. He hadn’t needed anything like this in his life but his instincts were howling for it, begging for a connection that couldn’t be taken and that belonged only to him.

Something that was unquestionably his. A connection that couldn’t be bought, traded or faked.

A low, possessive snarl sounded and Tony barely registered the light thud of the Alpha’s mask landing on the couch near his face. The fingers at his hips, one flesh warm and the other unyielding metal, dug in as he was jerked back into each thrust. Every drive of the Alpha’s hips forward had him going balls deep into Tony each thrust and the steadily swelling knot kept popping free until the Alpha slammed deep, rutting and snarling, before the growing knot finally slipped inside.

It caught just inside of him and started to swell, growing larger and pressing up against his sensitive inner walls, before Tony’s entire body locked up. His release slammed into him with all the grace of a train and Tony was almost sure the people in the gala could hear him lost to the pleasure of being knotted for the first time but it was nothing on being hauled up. While his Alpha’s cock pumped his release, hot and thick, into him sharp teeth broke the skin over his bonding gland and the bond snapped into place.

Tony was limp and sated, a soft sound of satisfaction the only thing escaping him, as the new bond practically sang between them. It was warmth and safety, reassurance that he wasn’t alone, and Tony had never imagined that he’d needed it so badly. It felt right. Everything had felt distant, off and disconnected, since his parents had died and now he felt blissfully tethered.

Anchored and safe. The tension he’d been carrying for years eased and Tony almost laughed hysterically at how fucking good he felt. “Wow.” His voice was wrecked, his body had gone completely pliant and Tony had never experienced an orgasm like that in all the time he’d spent discovering pleasure since he first discovered sex. He could feel how his inner muscles had started to squeeze down on his Alpha’s knot, milking it for every single drop, even while the rest of him didn’t seem to have an ounce of strength left to move.

“Mine.” The word was almost darkly possessive and satisfied, “My Omega.”

“Yeah. Yours.” Tony sighed, floating on pleasure, as he found himself still pressed up against the Alpha and the warmth of the leather he was still wearing. “Couldn’t even get out of your clothing, huh?”

There was no response to that but Tony didn’t care. At least the gala had been worth something. In this moment he couldn’t imagine why Howard had been so horrified that he was an Omega. He didn’t feel wrong or weak. He felt complete. Solid and right. Like a piece that had been missing was finally slotted back into place. His mind was still buzzing with ideas, improvements and innovation. Nothing had changed there.

If anything his mind felt clear in a way it never had before.

Warm hands lowered him back so he was bent over the couch and still caught on his Alpha’s knot. His Alpha’s hands didn’t waste any time before they were roving over his naked body, touching and teasing, while Tony laid there basking on the high of a good fucking and a new bond. It was a comfort he’d never expected, never planned for and it settled something inside of him. He laid there and breathed in their combined scent coupled with the scent of sex as his mind floated.

It was easy to drift when he was warm, safe and sated. So easy that Tony was dozing lightly by the end of his Alpha’s knot. He’d been running on little sleep to begin with and it was catching up now. A low protesting sound escaped his lips when his Alpha slipped free causing slick and come to lazily leak out. Tony wasn’t expecting to be wrapped up in something soft and warm, curled against a strong chest, as his Alpha left the room.

He watched through hooded eyes as his Alpha carried him down a hallway, mask back in place, until they reached a stairwell and then it wasn’t long until they were out in the cool night air. Tony didn’t think anything of it as he drifted and let himself fall deeper into sleep, bond thrumming between them and leaving him with a calming feeling, as he gave into exhaustion.

* * *

The Soldier carried his precious bundle towards the meeting point he was supposed to head to the instant he’d completed his mission barring complications. He glanced down at the warm, soft body in his arms and believed this counted towards a complication. The Winter Soldier, HYDRA’s Asset, had never encountered anyone who called to him like this Omega had.

His handler was waiting for him and the Soldier knew he was going to be punished by the look on the man’s face.

“Mission report.”

“Target was eliminated. No witnesses.”

He wasn’t sure what to say about the Omega and the subsequent claiming. The Soldier paused, hold tightening and body coiled tight, as he waited for a response. His handler’s dark eyes flicked over the Omega in his arms and he watched as they lingered on his Omega’s face. Nothing was said as a nod towards the vehicle had him moving. They wouldn’t punish him here. It wouldn’t be until they were out of the public view.

They needed the chair for that.

“You deviated from the mission.” His handler was in the front seat, “Why?”

It was a simple question. Not even an order but the Soldier knew there wasn’t a question that he was required to answer it. He didn’t go into specifics, “Instinct.” It was a simple response because that’s what it had been and nothing more. The second he’d caught the Omega’s scent something had clicked into place in his mind and he’d known that the Omega before him belonged to him. There hadn’t been a question as he’d breathed in the enticing scent and seen bright brown eyes staring at him from a pretty face.

Everything in him had strained towards the Omega and he’d seen it in the Omega’s eyes. The Omega knew that he belonged to the Soldier and instinct had guided him into claiming the Omega so the spark in the back of his mind turned into an almost cheerful kind of fire that was the warmest he’d ever felt in his memory.

It was warm enough he was sure not even the chill of being frozen would be able to bank it.

“Instinct.” His handler looked less than impressed. “Instinct told you to fuck and knot Tony Fucking Stark?”

Something in the Soldier reared up at the tone, at the insult to his mate, and he barely bit back the suddenly pressing need to choke the life out of the man glaring at him. His hands were full and he couldn’t risk harm to his Omega. “He is mine.” It was more detail then he’d thought necessary but the handlers often seemed to demand it and he was nothing if not efficient when it came to the missions he was given. He’d never failed and he hadn’t failed tonight.

What seemed to be obvious to him often required additional details for his handlers to understand.

He watched the glare slip and fall into something he would call shock. It was similar enough to the man he’d killed tonight, wide-eyed and mouth slightly agape, as he waited for his handler to either request further information or to respond to his answer. Regardless of his handler’s response if anyone tried to take his Omega the Soldier would be forced to eliminate the threat. He could feel the bond blazing in the back of his mind and he could feel the warm contentment from the Omega resting peacefully in his arms.

Their combined scents were both comforting and grounding in a way nothing had been. Everything was usually sharp, hard, cold and ordered. This was different. It was more and he would kill to keep it. It was nothing to stain his hands in blood.

They were already soaked in it.

“Tony Stark is your true mate.” The tone was stunned and not a question. His handler had stated it as fact. As silence hung in the air the Soldier shifted his hold, eyes flicking out the windows for possible incoming threats, before he settled once more on his handler.

“Yes.”

It was silent again and then a low chuckle sounded. “Unbelievable.” His handler shook his head, “Un-fucking-believable. And you claimed him?” at his nod another laugh escaped, “You’re even more of an asset then we thought.” His handler’s eyes turned calculating, “He’ll need to be enhanced. We can’t have him aging or dying and damaging our Asset in the process.” The Soldier watched as his handler called ahead, “Is there enough left for one more experiment?” a voice on the other end responded in an affirmative without seeming to need clarification on what his handler was requesting, “Good. I have our next candidate.”

The Soldier listened to the short silence and then, “ _Who_?”

“The Winter Soldier’s Omega." there was a brief pause before his handler continued, "Anthony Edward Stark.”

**Author's Note:**

> Wow. It's been awhile since I wrote for the Marvel fandom. I missed it. I'm hoping to get a feel for the fandom again while I break in this new account and then move from one-shots to multi-chapter fics. I'm mostly using one-shots to work out Tony and Bucky's voices, how I want to present them and to make sure I can keep the most important aspects of their characters in place despite whatever scenario I place them in (canon or complete AU). We'll see how it goes.
> 
> I'm hoping I managed to, at the very least, write a decent WinterIron fic for you all to enjoy even though it was mostly smut with only hints of actual plot.
> 
>  
> 
> [My Tumblr](http://the-winter-writer.tumblr.com)


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